Detection of coronary artery disease (CAD) before morbidity or mortality occurs is important to facilitate the possible modification of the atherosclerotic process. Deposition of calcium occurs early in the atheromatous process. This proposal requests continuing study of the early atherosclerotic process, by X-ray detected coronary artery calcifcation [CAC]) in a cohort of subjects from Muscatine, Iowa, initially examined during childhood and young to middle-age adulthood. It will allow the further study of the progression of CAC as it is affected by the aging process, established and putative risk factors. The aims of this continuation proposal are to: 1) develop a practical method to incorporate the use of a calcium calibration phantom into the CAC scoring algorithm, to increase the precision with which CAC is identified among subjects and within the same subject over time in large-scale epidemiologic investigations; 2) identify genetic risk factors for the presence and progression of CAC; and 3) characterize the prevalence and progression of coronary artery calcification (CAC) and the association of CAC with childhood, young adult, and concurrent risk factors in the CT Vascular Calcium Study cohort. This study has the potential to demonstrate that CRFs, measured in childhood and young adult life, identify individuals destined for premature atherosclerosis at a young age when preventive measures may be instituted to prevent morbidity and mortality.